Two thirds of US Dairy Herds infected with paratuberculosis.

In 2007, the United States Department of Agriculture’s (USDA) National Animal Health Monitoring Service (NAHMS) surveyed US Dairy Herds on a nationwide basis.

They found that 68.1% of US Dairy Herds are infected with Mycobacterium avium subspecies paratuberculosis (MAP), an obligate pathogen which causes Inflammatory Bowel Disease (Johne’s Disease) in cattle, sheep, goats and other food animals. Paratuberculosis is present in milk from infected animals, and is known to survive commercial pasteurization. Live MAP has been cultured from US retail milk supplies.

Mycobacterum avium subspecies paratuberculosis is suspected of causing the human Inflammatory Bowel Disease known as Crohn’s Disease, and there is mounting scientific and medical evidence that at least some proportion of Crohn’s Disease is caused by MAP. If MAP does cause Crohn’s Disease, then it is certain that the primary route of transmission of MAP to humans is through contaminated dairy and meat products.

The NAHMS study also found evidence for MAP in 95% of large dairy herds, an unprecedented figure which shows that MAP is spreading rapidly and unchecked through US herds of food animals. Not only is the milk from these cattle infected with MAP, but their carcasses, which are used to make ground beef, contain billions of MAP organisms.

The testing method used to detect paratuberculosis is known to underestimate the true prevalence. To quote the NAHMS report: “Although environmental sampling is an effective method of detecting operations infected with MAP, it will not detect all infected operations. Thus, reported percentages will be less than the true prevalences.”

The full report is available from the USDA Animal and Plant Inspection Service (APHIS) website.